TY - CHAP A1 - Sowinska, Małgorzata A1 - Das, Chittaranjan A1 - Wojciechowski, Konrad A1 - Snaith, Henry J. A1 - Schmeißer, Dieter T1 - XPS study of the ALD growth of Al₂O₃ on the CH₃NH₃PbI₃ T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - Organic-inorganic lead halide perovskites have emerged as very attractive absorber materials for the fabrication of low cost and high efficiency solar cells, but a delicate nature of these films is one of the main challenges for a successful commercialization. Typically, when exposed to air or moisture, perovskite films degrade within a couple of hours or days. Moreover, the methylammonium lead triiodide (CH₃NH₃PbI₃) perovskite cannot sustain a prolonged annealing at temperatures around 85∘C. In this work, we are investigating stability (upon air and thermal exposure) of a CH₃NH₃PbI₃ perovskite film coated with a thin layer of Al₂O₃ deposited by atomic layer deposition (ALD). In particular, the chemical and electronic changes occurred at the Al₂O₃/CH₃NH₃PbI₃ interface during the first 50 ALD cycles were monitored ex-situ by high-resolution and surface-sensitive synchrotron-based X-ray photoelectron spectroscopy (SR-XPS). The advantage of the ALD as a deposition method is that it can produce extremely dense layers with a very precise thickness control at room temperature. Detailed SR-XPS data analysis and a stability test of the perovskite film with alumina will be presented. KW - atomic layer deposition KW - perovskite solar cells KW - Al₂O₃ KW - X-Ray photoelectron spectroscopy KW - synchrotron Y1 - 2016 UR - http://www.dpg-verhandlungen.de/year/2016/conference/regensburg/part/cpp/session/31/contribution/6?lang=en SP - S. 206 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Sowinska, Małgorzata A1 - Das, Chittaranjan A1 - Wojciechowski, Konrad A1 - Snaith, Henry J. A1 - Schmeißer, Dieter T1 - Spectroscopic investigation of the nitrogen role in organic-inorganic perovskite films T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - Over the past few years, a wide range of device architectures employing organic-inorganic metal halide perovskite absorbers has been reported, with efficiencies exceeding 20%. Despite the tremendous progress, a number of key issues must be resolved before the wide-spread com- mercialization will be possible. Some of the primary challenges include lead toxicity, long-term stability, and fast degradation upon exposure to humid atmosphere. Recent computational and experimental studies suggest that hybrid metal-halide perovskites act as an ionic-electronic conductor. The study of vacancy-mediated migration of I−, Pb2+ and CH3NH3− ions and their relative activation energies suggests that migration of halide vacancies, to and from the interfaces in the solar cell during its operation, is the main conduction mechanism. In this work, we are presenting high resolution synchrotron-based spectroscopic study, which indicates that the contribution of nitrogen into the conduction mechanism of methyl ammonium lead iodide-based (CH3NH3PbI3) perovskite films should not be neglected. The N1s core level and resonant X-ray photoelectron spectroscopy at the N1s-egde of the CH3NH3PbI3 films are discussed in detail. KW - perovskite solar cells KW - X-ray photoelectron spectroscopy KW - nitrogen Y1 - 2016 UR - http://www.dpg-verhandlungen.de/year/2016/conference/regensburg/part/cpp/session/11/contribution/7?lang=en SP - S. 150 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - GEN A1 - Sowinska, Małgorzata A1 - Das, Chittaranjan A1 - Wojciechowski, Konrad A1 - Rouissi, Zied A1 - Snaith, Henry J. A1 - Schmeißer, Dieter T1 - Atomic layer deposition of Al2O3 on CH3NH3PbI3 for enhancement of perovskite solar cells stability T2 - Synchrotron Radiation in Natural Science : Bulletin of the Polish Synchrotron Radiation Society KW - atomic layer deposition KW - perovskite soloar cells KW - X-ray photoelectron spectroscopy (XPS) KW - Atomic foce microscopy (AFM) Y1 - 2016 SN - 1644-7190 VL - 15 IS - 1-2 SP - S. 33 ER -